Immunology Lecture 4. Flashcards Preview

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Flashcards in Immunology Lecture 4. Deck (15):

In what 7 ways does the secondary immune response differ from the first?

1 - shorter lag time 2 - higher rates of antibody synthesis 3- higher peak of antibody titer 4 - longer persistence of antibody 5 - IgG predominance 6 - higher affinity of antibody 7 - requires less antigen to begin


What is the difference between a toxin and a toxoid?

toxoid has toxicity inactivated/suppressed, while the immunogenicity is maintained - used to induce an immune response


What is the role of a B cell?

express surface immunoglobulin


What do B cells need to proliferate?

T cell help


What happens during clonal expansion of B cells?

increase in affinity by selective expansion -only the clones with the highest affinity will be stimulated ——> also make class switch to IgG from IgM and memory cells


What is the role of helper T-cells? (CD4)

limit B cells from making antibodies that attack self


What type of antigen do T-cells react to?

proteins or peptides on surface of presenting cell - these T cells will proliferate and stimulate B cells


What is the mechanism of a T-independent antigen?

cause a cross linking of the immunoglobulin on the B cell —> also through Toll receptors


What is an antigen presenting cell?

1 - initiate the interaction with antigen by endocytosis or phagocytosis, digest antigen for antigen presentation on MHC complex 2 - provide a co-stimulatory signal


What happens when there is presentation of antigen without co-stimulation?

nothing - NO IMMUNITY


What is the co-stimulatory signal?



Are B-cells capable of processing antigen, expressing class II antigen, and expressing co-stimulators?



What is MHC Class I?

presents endogenous antigens that originate in the cytoplasm (both self and foreign proteins) - on most cells


What is MHC Class II?

only on specialized immune cells - present exogenous proteins and are recognized by helper T cells


What two signals do T cells need for an antigen specific response?

antigen + MCH AND costimulator